ABSTRACT Emerging evidence implicates bile acid-intestinal microbiota interactions in the pathogenesis of pruritus associated with primary biliary cholangitis (PBC). Cholestyramine, a bile acid sequestrant, is clinically recommended for pruritus alleviation. This study investigates its regulatory effects on gut microbiome composition and metabolite profiles. A prospective cohort of 54 pruritic PBC patients and 25 asymptomatic controls underwent longitudinal multi-omics profiling. Fecal 16S rRNA sequencing and untargeted metabolomics were performed pre-/post-4-week cholestyramine intervention (4 g twice daily). Serum autotaxin, as a biomarker for pruritus assessment, and liver function tests were completed simultaneously. Four important findings were listed as follows. (i) Pruritus phenotype characteristics: Pruritic patients exhibited elevated cholestasis indices (total bilirubin, alkaline phosphatase ALP, and gamma-glutamyl transferase), higher ATX levels, and increased Gp210 antibody positivity compared to controls (all P < 0.01). Cholestyramine significantly reduced 5-D pruritus scores, ATX levels, and cholestasis markers ( P < 0.01). (ii) Microbial dysbiosis: Gut microbiota diversity (Shannon/Simpson indices) was markedly decreased in pruritic patients, with taxonomic enrichment of Romboutsia , Stenotrophomonas , and Achromobacter , whereas Lachnospiraceae and Bacteroidaceae predominated in controls. (iii) Metabolomic perturbations: Metabolomic analysis identified diminished medium-chain fatty acids and indole derivatives (e.g., norharman) in pruritic patients. (iv) Therapeutic efficacy: Microbial-metabolite-clinical correlations revealed the pivotal role of the Romboutsia -norharman-ATX/ALP axis in the pathogenesis of pruritic PBC. Post-treatment, cholestyramine restored microbial diversity, normalized metabolite levels, and attenuated pruritus. Enterobacteriaceae /long-chain fatty acids have been identified as a significant marker for predicting the efficiency of the response to cholestyramine. IMPORTANCE Pruritus in primary biliary cholangitis arises from synergistic cholestasis and gut microbiome-metabolite dysregulation. Cholestyramine mitigates symptoms by modulating the microbiome-metabolite-host axis, highlighting its therapeutic potential through microbiota remodeling and metabolic homeostasis restoration.
Zhou et al. (Mon,) studied this question.